Primary care practices are uniquely situated to deliver effective preventive services to the majority of Americans. However, because of most practices' limited capacity to change and isolation from systems and community resources, this potential has not been met. Our prior research has developed a community practice laboratory for cancer control research. In observational studies we discovered novel opportunities for practice-individualized approaches to enhancing prevention. Applying these insights in the STEP-UP clinical trial demonstrated sustainable increases in preventive service delivery. Multimethod process assessments of high and low change practices produced a new model for a multilevel, multistage intervention that engages practice, community and healthcare system resources. The proposed competing continuation project is a group randomized clinical trial. Thirty primary care practices, stratified by health care system affiliation, will be randomized to initial or delayed intervention groups. The intervention begins with a multimethod assessment of the capacity to change of each practice and its community and healthcare system. Insights from this assessment will inform a participatory approach to building practice change capacity and community and health care system linkages. These new capacities and connections will then be used to tailor sustainable approaches to preventive service delivery. The hypothesized effects of the intervention will be assessed on: practices' capability for change, rate of delivery of US Preventive Services Task Force-recommended preventive services, and patient and clinician satisfaction. Multilevel modeling will be used to control for clustering and any baseline differences between groups. Using an innovative set of multimethod procedures, the process of change will be assessed. The resulting insights will be used to design a refined multilevel intervention. This refined intervention will be implemented and evaluated in the delayed intervention group using a pre-post design, while long-term outcomes continue to be assessed in the initial intervention group. The resulting knowledge will be transportable to other systems seeking to improve the quality of health care.